Systems and methods exist for generating document authentication indicia that can be verified by conventional, non-electronic means. Such mechanisms have been used for centuries, so as to reassure a reader of a document that the document is authentic, that its source or author is as stated, and that the document has not been tampered with. Such authentication mechanisms can also provide a document recipient with a mechanism for ensuring that the author or signer of a document cannot later repudiate his or her authorship or assent to the document. Examples of mechanisms for performing these functions are handwritten signatures, seals (such as wax, embossed, or ink seals), non-erasable ink, and the like.
More recently, digital means for authenticating documents have emerged. Digital signatures, implemented by a combination of hash operations and asymmetric encryption, provide assurances as to document authenticity and integrity. Digital signatures are generally applied, transmitted, and verified by computers, in a manner that is usually invisible to users. Authors and signers generate digital signatures by activating commands in a software package or operating system, while document recipients and other users can verify signature authenticity by activating validation commands. In many cases, validation takes place automatically upon receipt of a document that requires it.
Each of these two methodologies has its strengths and weaknesses. Digital mechanisms are often more reliable and accurate and may be more convenient as long as the appropriate software and computer equipment are readily available. However, such techniques require complete trust in the computer system and software. Older visual-based methodologies appeal to some users by providing more tangible indicia that can be visually perceived, readily understood, and directly verified; many users consider such visual indicia to be more trustworthy than the mysterious processes that take place in digital mechanisms. Visual methodologies can also be used in situations where a computer is not available or is not convenient.
Since each mechanism has its advantages and disadvantages, it is not uncommon for some users to apply both traditional and digital authentication methods to the same document. However, such approaches do not generally integrate the two types of authentication. Rather, they are often even more cumbersome and inconvenient to apply, and often emphasize the disadvantages of the two methodologies rather than their strengths.
What is needed, then, is a technique that brings together the advantages of both authentication methodologies in a unified approach that streamlines and improves the processes of generating authentication indicia and verifying such indicia. What is further needed is a technique that provides users with the intuitive assurance of a visual authentication methodology, combined with the reliability and convenience of digital authentication methods.